Approximately 350,000 deaths occur each year in the United States alone due to sudden cardiac arrest (SCA). Worldwide deaths due to SCA are believed to be at least twice that of the U.S. incidence. Many of these deaths can be prevented if effective defibrillation is administered within 3-5 minutes of the onset of SCA.
SCA is the onset of an abnormal heart rhythm, lack of pulse and absence of breath, leading to a loss of consciousness. If a normal pulse is not restored within a few minutes, death typically occurs. Most often, SCA is due to ventricular fibrillation (VF), which is a chaotic heart rhythm that causes an uncoordinated quivering of the heart muscle. The lack of coordinated heart muscle contractions results in inadequate blood flow to the brain and other organs. Death typically ensues unless this chaotic rhythm is terminated, allowing the heart to restore its own normal rhythm.
Rapid defibrillation is the only effective means to restore the normal heart rhythm and prevent death after SCA due to ventricular fibrillation. For each minute that passes after the onset of SCA, the rate of mortality generally increases by 10%. If the heart is defibrillated within 1-2 minutes, survival rates can be as high as 90% or more. With delays of approximately 7-10 minutes, the survival rate drops to below 10%. Thus, the only effective solution to VF is early defibrillation.
Automatic External Defibrillators (AEDs) can provide early access to defibrillation, but they must be easy-to-use so that they may be administered by a broad range of first responders, portable so they can be easily carried to an SCA victim, and easily maintained so as to ensure high reliability. In addition, AEDs must be affordable, so that they can be broadly deployed and be readily accessible when a SCA event occurs.
AEDs require a portable energy source so as to enable the device to be rapidly deployed to timely treat an SCA victim. Often, the victim may be in a remote or difficult to reach location, making compact and portable AEDs most useful to police, emergency medical services (EMS), Search-And-Rescue teams and other rescue or emergency services.
AEDs must remain in a standby mode for extended periods of time and still be able to administer full power shocks when called upon for use. Most current AEDs are designed to be able to remain in standby mode for a period of two years and still retain the power to be able to administer the necessary shocks. During this standby period, the device must run self-tests to determine the readiness of the device. These tests must be run in an efficient manner to avoid draining the battery during this standby period.
Many current AEDs run automatic self-tests based on a predetermined test schedule, without taking into account prior device use, time of day, pre-programmed information, operational features and previous events.
Thus, there is a need for a new and improved system and method for performing self-tests in an AED.